Previous cargo hooks with automatic cargo unloading capability have been complicated in nature with many moving parts, lacking in automatic loading capability, and loading and unloading of capability with the hook in mid-air.
Other cargo hooks with automatic unloading of the load cable have lacked back-up positive load retention, wherein accidental application of signal to unload suspended cargo has been possible.
Another problem has been ready inspection of the device for imperfections, wear and tear. Then fabrication of the device has been labor intensive, the large number of parts needed to be assembled by a skilled mechanic; thus, maintenance and initial costs of the device have been appreciable.
Breeze-Eastern, Union, New Jersey is America's largest supplier of cargo hooks to the military services. To unload suspended cargo remotely, the application of a signal to a solenoid within the hook device is required from an external switch.
What happens if the voltage fails due to possible injury to the wires connected to the solenoid and electrical continuity is lost?
In one of the inventor's configurations, no voltage application is required, even with back-up position load retention. A cord is provided so that when pulled the load cable is capable of being released. However, the load cable still is not released until the cargo touch-down and the hoist cable slackens.
Automatic `loading` and unloading of suspended cargo is desirable in ship-off-shore material handling operations, in removal of toxic containers and other toxic waste material in industrial plants, and in removal of radon soil containers. The devices described herein also may be applied to the rescue of personnel from damaged ships and from mountainous regions of a country where a mountain climber may have become disabled. Present cargo hooks do not have automatic `loading` capability